Flash-based audio and video communications in the cloud

Internet telephony and multimedia communication protocols have matured over the last fifteen years. Recently, the web is evolving as a popular platform for everything we do on the Internet including email, text chat, voice calls, discussions, enterprise apps and multi-party collaboration. Unfortunately, there is a disconnect between web and traditional Internet telephony protocols as they have ignored the constraints and requirements of each other. Consequently, the Flash Player is being used as a web browser plugin by many developers for web-based voice and video calls. We describe the challenges of video communication using a web browser, present a simple API using a Flash Player application, show how it supports wide range of web communication scenarios in the cloud, and describe how it can interoperate with Session Initiation Protocol (SIP)-based systems. We describe both the advantages and challenges of Flash Player based communication applications. The presented API could guide future work on communication-related web protocol extensions.

More details are available in our white-paper. The associated software and example use cases are available as flash-videoio and siprtmp projects. The white-paper also serves as the architecture and design document of these projects.

Documenting RFC implementations

Just wanted to document how I am using the existing documentation such as IETF RFCs and Internet-Drafts in my 39 Peers project. You can looks at some samples at here or here.

I wrote a htmlify.py script. The script uses the SilverCity python package to decorate the base python code. To include the documentation from RFCs, the script interprets the python source code to identify lines such as

# @implements RFC2617 (HTTP auth)

If found, it downloads the particular RFC from IETF website, removes any formatting empty lines such as near page breaks, and numbers all the pages and lines. It then stores the resulting file as a text document which you can lookup and use in your documentation.

Furthermore, the script identifies lines such as

# @implements RFC2617 P3L16-P3L25

If found, the line is replaced by a HTML DIV block with content of the documentation in RFC2617 text file from page-3 line 16 to page-3 line 25.

I find this technique pretty handy, and keeps my decorated source code with inline documentation extracted from RFCs and drafts, instead of I having to write extensive document.

First post: initial set of references

The recent news is that I am back from a long stay in India of about five months. I decided to start a new blog to put together my findings and readings on P2P-SIP and VoIP in general. If you would like to be added a team member for this blogger please drop me an email and I will add you!

I will start with references to my work. You can see a brief overview of our P2P-SIP design as a short paper, a more detailed architecture document or an extended overview paper. I also have an implementation running on Linux. The implementation report describes the details of the implementation so that others can also implement similar system.

There are many other papers on the p2p-sip website, including the original SoSIMPLE technical report, and internet drafts by Alan Johnston, Nimcat Networks and College of William and Mary.